Water shortages in many areas of the world have increased the need for more technologically advanced, more efficient, and higher capacity systems for production of drinking water, production of water for agricultural uses, and wastewater reuse. One approach that has been used for water desalination includes a reverse osmosis desalination skid fed from an intermediate storage tank containing water filtered by another approach, such as ultrafiltration or microfiltration. The intermediate storage tank typically separates ultrafiltration modules that feed the storage tank, where filtrate stored in the storage tank is then fed to the reverse osmosis desalination skid.
Because high flow rates through these desalination systems typically require a large intermediate storage tank, these systems can have a correspondingly large system footprint. It may therefore not be possible to deploy these desalination systems in environments in which space is limited. Moreover, the intermediate storage tank can result in additional requirements, such as additional pumps that can further increase the system footprint, and system shutdown control requirements associated with operational emergencies that may result in an empty or a full intermediate storage tank. In addition, backwashing of the ultrafiltration modules has typically been done with filtered water from the intermediate storage tank, or with the permeate output from the reverse osmosis desalination skid. This can reduce the output flow rate and the efficiency of these desalination systems and can further increase size requirements of the intermediate storage tank.
Also, under various field conditions feed water salinity may vary temporally and thus system operation may not be energy optimal, since conventional systems are typically designed to operate at a fixed recovery and/or a fixed feed flow rate. Raw water feed quality can also vary over time, which can affect filtration needs (prior to membrane desalting). Conventional systems typically operate with a cleaning frequency or duration that does not automatically adapt based on feed water quality.
It is against this background that a need arose to develop the apparatus, system, and method for integrated filtration and reverse osmosis desalination described herein.